O U T L I N E

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UPDATE ON THE FORWARD PROTON DETECTOR
Gilvan Alves Lafex/CBPF

• Introduction
• Accelerator
• Roman Pots
• Detector
• Future Plans

April 1, 1998 (no kidding)
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FORWARD PROTON DETECTOR
Roman Pot
Bellows
p
p
Detector
A1Q
P1Q
A1S
P1S
S
D
Q1
Q4
Q2
Q2
Q3
Q3
Q4
S
A2Q
A2S
P2S
P2Q
AD2
AD1
59 57 36 31 23 19 13 7
0 7 13 19 23
31 Z(m)
Series of 18 Roman Pots forms 9 independent
spectrometers 1 Dipole Spectrometer ( p ) x gt
xmin 8 Quadrupole Spectrometers (p or p, up
or down, left or right) t gt tmin
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Diffractive Kinematics

• Rapidity Gap Approach
• Need to Tag and Measure p( p )

p

Detector
4
The Detector
UVX Planes
0.8mm
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PROPOSAL FOR A FORWARD PROTON DETECTOR AT
DZERO (P-900)
Andrew Brandt FNAL/
1) PHYSICS MOTIVATION 2) FPD DETAILS
Fermilab PAC meeting Fermilab October 17, 1997
6
ACCELERATOR MODIFICATIONS
1) Move low beta quadrupoles 2/3 meter
closer to the interaction point. Requires
modified quadrupole supports. 2)
Insert pots in electrostatic separator region.
Requires bypass extension.
Bypass extended
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ACCELERATOR MODIFICATIONS

• 3) Dipole Spectrometer does not require
• modifications ? Warm section exists.
• Feasibility and Cost Studies done in conjunction
• with Beams Division (see Memo).
• No interference with Tevatron operation
• Total Cost ? 500k (Mostly Engineering Labor).
• An Engineer from Brazil will work with the
• AD on the modifications.
• Mike Martens has joined the FPD group and
• will act as the Beams Division Liaison Person
  
• for this project.

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FRONT VIEW OF PROPOSED ROMAN POTS
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SIDE VIEW CROSS SECTION
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Full Scale Model Presented at Lishep98 - Rio
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Full Scale Model Presented at Lishep98 - Rio
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Full Scale Model Presented at Lishep98 - Rio
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Further Development in Progress

• Reducing Pot Long Neck Size
• Interface with Pumping Devices
• Chainless Design

• Agreement Signed with LNLS for
• Prototype building this spring
• LNLS - National Synchrotron Lab
• Helps on Funding
• Prague group is Helping with
• design Vacuum expertise

14
THE DETECTOR
Six planes (u,u,v,v,x,x) of 800 m
scintillator fibers () planes offset by
2/3 fiber
20 channels/plane(U,V) 16 channels/plane(X,X) 11
2 channels/detector 2016 total channels 80 m
theoretical resolution
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THE DETECTOR
4 Fiber bundle fits well the pixel size of H6568
16 Ch. MAPMT 7 PMTs/detector (most of the cost)
U
U
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• Photon Detection Device
• Quantum Efficiency
• Light ? Charge
• VLPC (? 80)
• APD (? 70)
• Image Intensifier
• CCD (? 20)
• Low rate
• MAPMT (? 20)
• VLPC the best option
• But... cryogenics

18

DETECTOR OPTIONS

• Fiber Options Investigated
• Scint. Tile to Clear Fiber
• Scint. Tile to WLS Fiber
• Scint. Fiber Straight
• Scint. Fiber to Clear Fiber
• Round vs. Square Fibers

19

DETECTOR OPTIONS
4fibers ? PMT
Scint Tile 800?m thick
Clear Fiber
2 WLS fibers ? PMT
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DETECTOR OPTIONS
Mirrored side
4fibers ? PMT
Scint Fibers 800?m
Mirrored side
4fibers ? PMT
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Single PE Measurement H6568
LED Calibration.
Scint. Tile Clear Fiber
ltNPEgt3.0
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Scint. Fiber Output H6568
ltNPEgt7.3
Effect of cutting Fiber at 45?
ltNPEgt6.8
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ltNPEgt7.4
Scint. Fiber Clear Fiber Output H6568

• Similar to Uncut Straight Fibers
• Gain Attenuation length
• Losses due to
• Cutting Fiber at 45? (5)
• Fiber Splicing (5-10)
• Preferred Option
• Accelerator Background
• Cross Talk

25
Current Developments

• 0th order Fiber detector Prototype being tested
• DAQ for prototype testing has been assembled
• Modifications to Splicing Machine being made
• Work on adapting CFT Trigger System
• Work on FPD Trigger strategy in progress

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1998 Plans

• Finalizing Detector and Pot Designs
• Both Prototypes Ready by Fall
• Request for National Grant within Brazil
• Project Integration within accelerator and D?